[eNotes policy limits the number of answers we can give.]
The most significant event that occurs in The Giver between chapters 8 and 15 is that Jonas is selected Receiver of Memory and begins his training with The Giver. After the training begins, Jonas is changed forever. He begins to understand the truth about his community on a deeper level.
In a community where fitting in is all that matters, Jonas has always been a little different. He has pale eyes, and sometimes sees things people do not. When the Ceremony of Twelve assigns each of his classmates a job, Jonas is skipped!
"Jonas has not been assigned," she informed the crowd, and his heart sank. Then she went on. "Jonas has been selected." (ch 8, p. 60)
Jonas begins his training alone with the old man known as The Giver. He learns that the community once had differences, and people used to have choices. Some of the memories are painful, but Jonas remains strong. He is committed to helping The Giver reduce his burden, and learning as much as he can about his community.
Lowry, Lois (1993-04-26). The Giver (Newbery Medal Book). Houghton Mifflin Harcourt. Kindle Edition.